Gas mixer



' June 11, 1940.

s. P. JONES 2,203,961

GAS MIXER Filed Aug. 23, 1931 3 Sheets-Sheet 1 5am I? clones June 11, 1940.

s. 'P. JONES 2,203,961

GAS uixr-m Fi led Aug. 23, 1937 3 Sheets-Sheet 2 jn-ucnfor,

Sam P clones June 11, 1940.

.s. P. JONES 2,203,961

GAS MIXER Filed Aug. 23, 1937 3 Sheets-Sheet 3 glnocnfo'p 5am P. clones a "to! t Patented June 11, 1940.

T UNITEDSTATES PATENT OFFICE 2,203,961 GAS, MIXER Sam P. .lones, Dallas, Tex. Application August .23, 1937, Serial No. 160,405

13 Clainisfl (c1. 4s 1s0 This invention relates to new and useful improvements in gas mixers. i i

One object of the invention is to provide an improved gas mixer for gas engines which is operated by the suction of the engine, whereby the gas and air are correctly proportioned and controlled by said enginesuction to maintain the operating efiiciency of loads and conditions.

An important object of the invention is to pro- :the engine under all vide an improved gas mixer wherein the means for controlling the flow of gas into the engine is located out of the pathof the incoming air, whereby said air does not Contact the same and any dirt, or other extraneous matter in said air cannot'faccumulate or adhere to said control means toimpairits efficient operation. Another object of the invention is to provide an improved gas mixer wherein the gas is controlledby a movable member which is adapted to engage a flexible or soft seat, whereby a. positive cut-oil of the gas is obtained.

A further object of the invention is to provide an improved gas mixer having'a stationary tubu larpostor member through which the gas flows,

with a sleeveslidable on said post for controlling the air entering the engine and also for control ling the air passing from the interior of said post, said sleeve being actuated or moved by thesuction of the engine, whereby both the gas and air supply are controlledby said engine suction.

Still another object of the invention is to provide an improved gas mixer having a movable sleeve member which not only controls the admission of air and meters the flow of gas entering the engine, but also controls the openingand closing of a positive cut-off valve for said gas; the member having a diaphragm connected thereto which diaphragm is exposed to the engine suction, whereby an increased area for the suction to act upon is provided, thereby resulting in ac tuation of the mixer regardless of the speed of l the engine.

A still further object of the invention is to provide an improved gas mixer having a control member slidable on a stationary member for controlling the admission of gas and air to the engine and so constructed that the contacting surfaces between the surface is not depended upon to out 01f thefiow of gas when the mixer is inactive,

whereby a slightclearance between the members i may be provided to assure operation or slidingof the movable member. l Afparticular object of the invention is to provide amgas mixer which has means for connecttaken on the line T- -l of Figure 3,

ing its air chamber with the regulator controlling thefiow of gas to its gas chamber, whereby any i change in the volume of air entering the mixer results in a proportionate change in the incoming gas. a

Another object of the invention is to provide a gas mixer employing a diaphragm exposed to the engine suction, with means for preventing rupturing of or injury to said diaphragm in the event that the engine brackfires.

A construction designed to carryout the invention will be hereinafter described, together ,with other features ,ofthe invention,

[The invention will be, more readily understood from a reading of the following specification and byreferencehto the accompanying drawings, in which an example of the invention isshown, and, wherein:

Figure l is an elevation of a gas, mixer, constructed in accordance with the invention, and 2 connected to the intakemanifold of an engine,

' as well as to an ordinary gas regulator,

Figure 2 is atransverse, vertical sectional view with the mixer in a cut-oif position,

Figure 3 is a similar view, withthe mixer admitting gas and air to the engine, t

Figure 4 is a View, similar to Figure 3, showing the position of the parts in the event that the engine backfires, 5 Figure Sis a horizontal, cross-sectional taken on the line ,5--5 of Figure 2,

Figure 6 is a horizontal, cross-sectionalview, taken on the line 6-6 of Figure 2,

Figure 7 is ahoi'izontal, cross-sectional view,

view,

Figure 8 is an enlarged, vertical, sectional View of the gas cut-off valve,

Figure 9 is a view similar to- Figure 2 showing a modified form of gas valve construction, with said valve in a closedyposition', l 40 Figure 10 is a similar view with the valve in i an open position, i i

Figure llis a horizontal, cross-sectional viewfl taken on the line l,ll I of Figure 10,

Figure 12 is an enlarged view showing the construction of the modified form of valve, and

valve it the passage oi gas and air through the bore it into the manifold'i'i may be readily controlled. v

' Belowthe neck ii, enlarged as shown at it; to form air chamber C and a collar is which is preferably made integral with said section extends radially therefrom. The chamber C is open. to atmosphere whereby air may enter the same and flow upwardly through the face of the neck to the manifold.

If desired, a suitable air cleanor (not shown) may be mounted on the collar iii. The

upper half of a diaphragm case 2b is formed integral with the lower end of the section A and is provided with an outwardly directed annular flange 2|.

' The lower half of the diaphragm 22 having an external annular flange 23, is formed at the upper end of the section B of the housing. Av

flexible diaphragm has its peripheral edge portion clamped between the flanges 2i and it, which flanges are secured together by bolts E25 and nuts il li, The central portion of the diaphragm is suitably reinforced inithe usual manner by a metallic plate 2e.

A cylindrical skirt 2'! depends from the lower half 22 of the diaphragm case and has an internally screw-threaded collar 28 extending radially therefrom. The collar receives one end of a gas'inlet pipe or conductor 29 whereby gas is conducted into the bore 30 of the skirt. The bottom of. the diaphragm case 2!! has a circular opening 35 therein which opening is in axial alinement with the bore of the skirt and the diameter'of said opening is less than the diameter of the bore, so as to form an internal annular shoulder 32 at the upper end of the bore. A tubular. guidepost or -member 33 is located within the skirt and has its upper end extending through the opening M in the bottom of the diaphragm case and also through an opening 34 in the diaphragm, whereby its upper end projects into the air chamber C. The top of the post is closed and terminates some distance below the neck I I at the upper end of the section A.

An external flange; 35 is provided on the post and abuts theinternal flange 32 at the upper end of the bore 3B of the skirt 2?. Below the flange thepost or member is slightly enlarged to form an internal valve seat 36.within the post. The diameter of this enlarged portion of said post is less than the'diameter of the bore 30 to permit gas entering the bore from the inlet pipe 29 to, now into the annular space between the exterior of the post and the bore 39. In 'a'linement with the lower end of the skirt, the post or member 33 is provided with a second external flange 3'! having substantially the same diameter as thebore andthis flange is disposed within said-bore, and rests upon'a retaining ring 38 which is fastened to the lower edge of the skirt 2! by bolts 39. A suitable packing gasket 39 is j interposed between the ring and skirt to prevent leakage'of thegas from the bore of the skirt.

. The distance between the flanges 35 and 31 is such that when the ring is engaging the latter flange, the flange 35 is held in engagement with the shoulder 32. This engagement is sufficient to.

. which is secured thereto by bolts M.

the upper section is prevent leakage of gas past the shoulder 32 but yet permits a rotation of the post or member 33 with relation to the skirt 2'! and diaphragm 24.

The extreme lower end of the post 33 or that portion below the flange 3?, depends beyond the retaining ring 38 and is closed by a plate 40 An indicating arm 42 is fastened to the plate and is curved upwardly so that its upper end extends contiguous to the exterior of the skirt 2! at its lower end. 7 The skirt may have graduations or other markings thereon and when the post 33 is rotated within the housing, the arm 42 indicates its position therein, as will be explained.

From the foregoing, it will be seen that the gasmay enter the bore 36 of the skirt 21- and may flow into the annular space between the bore and the lower end of the post. For permitting this gas to flow into and upwardly through the post or member 33, said post is formed with a plurality of radial ports 43 which are located immediately below the flange 35 and internal valve seat 36. The gas which passes through these ports flows upwardly through the post 33 and escapes therefrom through an armate slot or opening Mat the upper portion of said post. The slot M preferably extendshalfway around the post, as is clearly shown in Figure 6, and the gas passing through slot may flow upwardly through the neck H at the upper end of the section A and then into the intake manifold M.

For controlling the flow of gas through the ports 53 and upwardly through the tubular post 33, a valve assembly & is mounted within the lower end of the bore of said post below the valve seat 38. This valve assembly includes a valve member or piston 46 which has a sliding fit within the bore of said post and aflexibla ring H is secured to the topof said piston. A coiled spring 48 is confinedwithin the bore between the underside of the piston and the closure plate 40 and exerts its pressure to constantly urge the piston upwardly so as to hold the flexible ring 4? in engagement with the seat 36. The valve ring is constructed of rubber or other suitable material and obviously, when. engaged with the seat 35, is distorted to some extent, whereby the seat is embedded therein to prevent any leakage of gas thereby.

Movement of the valve member off its seat must be accomplished against tension of the spring 48 and for opening said valve member to permit gas to enter the tubular post 33, a sleeve 49 surrounds the upper end of the post and is slidable thereon. This sleeve hasits lower end flanged and suitably secured to the upper side of the diaphragm 2d. The upper portion of the sleeve is offset or enlarged at one side as shown at 5U in Figures 2, 3 and 5 and this enlarged portion extends around substantially one half of the sleeve to, form an arcuate passage 5| therein. The upper end of the sleeve is flared outwardly at El and is adapted to engage the top of the chamber C adjacent and surrounding the bore iii of the neck ll. When the diaphragm 24 is in a normal position, the sleeve 49 is raised with its upper end closing the bore of. the neck ll whereby air from the chamber C cannot pass the manifold. At this time, the passage 5| formed within the upper portion of the sleeve is above the arcuate slot in the post 33 and said slot is closed by the sleeve. 7

The underside of the diaphragmi l is exposed to the suction of the engine through ayertical passage 52 which extends downwardly through the wall of the poster member 33 and when the engine is started, the suction acts upon the crosssectionalarea of the diaphragm to move the same downwardly (Figure 3). Downward movemerit of thediaphragm slides the sleeve 49 downwardly whereby its upper end thereof moves v away from the top of the chamber C to permit the air therein to enter "the manifold M. At the same time the passage 5| formed by the offset 50in the sleeve uncovers a portion of the arcuate slot 44 in the post, the particular portion which is uncovered being dependent upon the movement; of the sleeve. l

As the air is admitted to the manifold and the engaged by a bar 54 which extends transversely within the sleeve and manifestly, downward movement of the sleeve will move said rod downwardly. The lower end of the rod extends into the axial bore 55 of a flanged head 56. Thehead is mounted within an axial opening 51 in the valve member 46 and ring 41 and has its flange overlying said ring. The lower end of the bore of the head is closed by a screw 58 and the pointed lower end of the rod 53 engages said i screw. When the rod is moved downwardly the valve member or piston 46 is moved downwardly under tension of the coiled spring 48 whereby the flexible ring 41 is disengaged from. the valve seat 36. 1

It is noted that the point of contact between the sleeve 49 and the rod 53 is some distance above the diaphragm which. is the element exerting the force; also the point of contactbetween saidrod and the valve member 46 is below the point at which the spring 48 engages the mem-- ber and therefore, the side pull on the rod when the diaphragm is depressed, is negligible. This eliminates any tendency of. the sleeveto bind on the postas it is moved in a vertical or straight line, thereby preventing excessive wear on the sleeve and post. i

In operation, when the engine to which the gas mixer is attached is started, the partial vacuum created in the intake manifold l4 will act against the underside of the diaphragm, 24

through the port or passage 52 in the post 33.

formed by the enlarged portion 50 of the sleeve 5 opening is uncovered. This establishes a communication between the interior of the post or member 33 and the bore 15 of the neck II as well as the manifold M, 3

The downward movement of the sleeve which admits air to the engine manifold anduncovers .clearly shown in Figure 3.

the gas from the inlet pipe 29 may flow through ing the efficiency of the movable parts.

a portion of the slot 44 also imparts a downward movement to the valve member 45 through the medium of the vertical rod 53. The rod is moved downwardly by the engagementof the transverse bar 54 with its upperend and since its lower.

end engages the screw 58 within the head 56 of the valve member, it will be manifest that the valve member is movedoif of the seat 36, as is When this occurs,

the radial ports 43 in the lower end of the member 33 after which it may enter the interior of said member; The gas from the interior of the member may then flow outwardly through the slot. or opening 44, upwardly through the neck H and into the manifold l4 of the engine. The

mixing of the air and gas takes place within the bore 15 of the neck I l and also within the intake manifold [4 prior to its passage to the cylinders of said engine. It is pointed out that there is no restriction of the gas flow at the valve member 45 for obviously when the member moves off the seat, 36 the gas may flow into the post 33 from any direction around said seat. However,

escaping from the member 33, the gas must pass through the arcuate slot 44 which extends only half way around said post. The area which is uncovered at the seat 36 is twice as great as the cross-sectional area of theslot 44 and therefore the restriction or control of the gas entering 44 and not at the valve member 45.

The amount of gas which escapes from the slot can be readily controlled by adjusting the member 33 to register more or less of the slot 44 with the passage 5| in the sleeve. This adjustment ing the manifold l4is accomplished at the openis accomplished by rotating the member 33 with relation to the sleeve and the mounting of said member ,is such that the frictional engagement of its flanges 35 and 31 with the shoulder 32 and ring 38 is sufficient to hold said member in its adjusted positions. The positionof the slot with relation to the passage is indicated by the indicator arm 42 which is outside of the skirt 21.

The air which is entering the manifold l4 from the chamber contacts only the upper end or outer surface of the control sleeve 49. This air does not have to pass over the contacting surface between the sleeveand the stationary post 33 and therefore there is no danger of any dirt or grit which maybe present in the air impair- This is an important feature of the invention as obviously the inner surface of the sleeve is kept clean at all times sincethere is substantially no dirt present in the incoming gas.

The suction of the engine at all times controls the amount of gas and air entering said engine and if the same is accelerated, the suction is prosaid manifold, It is noted that the air chamber C extends completely around the sleeve 49, whereby said air may enter the neck ll circumferentially, If desired, the upper end of the sleeve 49 may be curved inwardly as shown at 59 in Figure 13. This curve-du-pper end of the sleeve may extend into the bore l5 of the neck whereby theair entering said bore is directed toward the center thereof to assure its complete admixture with the gas passing upwardly through the sleeve 3d. At the same time the upper end of the sleeve 49 is seated against the lower end of the neck il -by means of the rod 53 engaging the bar 54. The engagement of the sleeve with the lower end of the neck immediately cuts off the air entering said neck. The flexible ring Al at the upper end of the valve member strikes the seat 36 and being flexible, it will be seen that said seat embeds itself within the ring, whereby a gas-tight seal is had at this point. Thus the gas and the air passing to the manifold Hi are shut off upon the upward movement of the valve member and sleeve. The parts remain in this position. until 3 the engine is again started. a

To prevent rupturing or otherwise injuring the diaphragm 2A in the event that the engine backfires, said diaphragm is formed with a plurality of openings 2 1 which are disposed adjacent the lower end of the sleeve 49. Normally these openings overlie the metallic reinforcing plate 26 and so long as the diaphragm is moved more or less gradually, said openings engage and are covered by said plate. If the engine backfires, the sleeve and diaphragm would be suddenly and quickly moved downwardly to the position shown in Figure 4. This sudden movement of the diaphragm would'cause the diaphragm to leave the metallic plate 25, whereby the openings 24' are uncovered. When so uncovered any gas' or air which is trapped beneath said diaphragm may escape outwardly through these openings. Therefore a sudden downward movement of the diaphragm would not rupture the same as the openings provide a relief for the escape of any gas or air which may be trapped therebeneath.

The upper section A of the housing is provided with a port 5| which communicates with the interior of the air chamber C. This port is internally screw-threaded so as to receive a connection or conductor 62. The other end of the conductor 62 (Figure 1) is connected to the vent 63 of the diaphragm chamber 64 of a gas regulator 55. The inlet pipe 29 is also connected to the gas regulator 65 in the usual manner and the gas flowing into the bore of the skirt 2'! is con-. trolled by said regulator. The pressure of the air within the chamber C is thus directed against the usual diaphragm 66 within the regulator and is added to the spring 67 to resist movement of the diaphragm. The spring El is adjusted so as to properly control the gas flowing through the conductor 29 into the skirt 21. So long as the volume of air entering the chamber C is maintained, the volume of gas entering the skirt 2? is regulated so that a proper amount of gas and airis passing to the manifold [4. However, in the event that the volume of air within the chamber C should undergo a change for any reason whatsoever, such as if the air cleaner becomes dirty or clogged and prevents suflicient air passing into the chamber, then a resultant change in air pressure within the diaphragm chamber 64 will occur. This change in pressure within the chamber 6 will cause a change in the regulation of the gas flow passing through the conductor 29 and therefore the amount of gas entering the skirt 2? will immediately be cut down in proportion to the change within the chamber C. It is pointed out that this hook-up of the gas mixer with the usual regulator is entirely optional and if it is not desired to use said regulator, the opening 6! in the housing 10 may be plugged. I

In Figures 9 to 12 a slightly modified form of the invention is shown. In this form, the tubular post or sleeve 33 is eliminated and a post 33 is substituted therefor. Theupper portion of the post 33' is similar in construction to the post 33 but said post 33 terminates at a valve-seat 36 which is disposed at the same point as the valve seatdfi. A flange 35' surrounds the valve seat 36 and a plurality of vertical pins 68 have their upper ends engaged in the flange 35'. The pins are shouldered and have spring washers 69 confined between the shoulder thereon and the underside of the flange 35'. The lower ends of the pins 68 are confined within a cap or closure "ill which is inserted in the lower end of the skirt Z'l of the housing. The cap is flanged and is held within the skirt by a retaining ring ll secured thereto by bolts '12. The cap or closure 10 has the indicating arm 42 fastened to itsunderside.

Instead of the valve member 45, a valve member it is provided and includes a metallic disk M having a flexible disk 15 on its upper surface. A vertical rod '53 extends through the disks i l and i5 and has its upper end bolted to the transverse bar 54'. of the sleeve 49, whereby said sleeve is connected to the valvemember 13. A coiled spring 16 is confined between the underside of .the disk M and the closure 70 to urge the Valve upwardly against the seat 36. The operation of this form is exactly the same as the first form hereinbefore described.

What I claim and desire to secure by Letters Patent is:

l. A gas mixer for an internal combustion engine having an intake manifold including, a housingadapted to be connected to said intake manifold of the engine and-having a gas inlet and an air inlet, the housing also having a gas passage leading from the gas inlet and having a port establishing communication between the passage and the manifold, said housing also having a fuel opening which communicates with the manifold, pressure responsive means within the housing exposed to the engine suction. and actuated thereby, movable means within the housing secured to the pressure responsive means movable with relation to the air outlet for controlling the admission of air to the manifold and also for co-acting with the port leading from the gas passage for controlling the gas flowing from the passage to said manifold, whereby the gas and air flowing to the manifold is proportioned by said means, a valve seat within the gas passage between the gas inlet and the port which estab-- lishes communication between the passage and manifold, a valve adapted to engage the seat and having a flexible seating surface whereby a positive gas cut off is had when said valve is seated, and means for connecting said valve to the movable means so that said valve is operated thereby.

2. A gas mixer for an internal combustion engine having an intakemanifold including, a housing adapted to be connected to said intake manifold ofthe engine and having a gas inlet and an air inlet, a tubular member within the housing having a gas inlet at its lower end communicatingwithth'e gas inlet in the housing and an outlet port in its upper portion so that gas may flow into the manifold from said member, the

housing also having a fuel opening which c.0m-

being movable relative to the full opening for controlling the admission of air to the manifold, and a pressure responsive element connected to the sleeve and to the housing and exposed to the suction of the engine for moving said sleeve toiuproportion the admission of air and gas to the manifold.

3. A gas mixer for an internal combustion engine having an intake manifold including, a housing adapted to be connected to said intake manifold of the engine and having a gas inlet and an air inlet, a=tubular member within the,

housing having a gas inlet at its lower end and an outletslot in its upper portion so that gas mayfiow into the manifold from said member, the housing also having a fuel opening which communicates with the manifold, a sleeve slidable on said member for closing, the outlet slot therein to cut off the gas to the manifold, said sleevealso being movable relative to the fuel opening for controlling the admission of air to the manifold, a pressure responsive element con nected to the sleeve and to the housing and exposed to the suction, of the engine for moving said sleeve to proportion the admission of air and gas tocthe manifold, and a positive cut offvalve within the tubular member between the gas inlet and the outlet slot and connected with the sleeve for controlling the admission of gas to the i 4. A gas mixer for an internal combustion engine having an intake manifold including, a housing adapted to be connected to the intake manifold of the engine and having a gas inlet and an air inlet, a tubular member within the housing having a gas inlet at its lower end and an outlet port in its upper portion so that gas may flow into the manifold from said member, said housing also having a fuel opening which communicateswith the manifold, a sleeve slidable on said member for closing the outlet port therein to out off the gas tothe manifold, said sleeve also being movable relative to the fuel opening for controlling the admissionof air to the manifold,

a pressure responsive element mounted within the housing and connected to the sleeve and exposed to the suction of the engine for moving said sleeve to proportion the admission of air and gas to the manifold, a valve seat within the member and located between the gas inlet and the outlet opening, and a valve having a flexible seating surface arranged to engage the seat for controlling the flow of gas into the member.

, 5. A gas mixer for an internal combustion engine having an intake manifold including, a housoutlet slot in its upper-portion to permitgas to escape therefrom to the manifold, the housing a also having an opening which communicates with the manifold, a sleeve slidable on the member and having its upper end movable relative to the opening for controlling the admission of air from the air chamber to themanifold, said sleeve having an arcuate passage therein adapted to register with the arcuate outlet slot to uncover the same to permit the gas to flow to the manifold,

, inlet of; the housing whereby gas may flow into the member, said member having an arcuate outlet slot in its upper portion to permit gas to escape therefrom to the manifold, the housing also having an opening which communicates with the manifold, a sleeve slidable on the member and having its upper end movable relative to the opening for controlling the admission of air from the air chamber to the manifold, said sleeve having an arcuate passage therein adapted to register with the arcuate outlet slot to uncover the same to permit the gas to flow to the manifold, a diaphragm mounted within the housing and connected to the sleeve and exposed to the engine suction to move saidsleeve to admit the air and gas to the manifold in predetermined proportions, and means for preventing rupturing said diaphragm in the. event that the enginebackfires. if i 7. A gas mixer for an internal combustion engine having an intake manifold including, a housing having a gas inlet and an air chamber therein and adapted to be connected to the manifold of an engine, said housing also having an opening which communicates with the. manifold, a tubular member rotatably confined within the housing and having a gas inlet in its lower end communicating with the gas inlet in the housing whereby gas may flow into the member, said member having an arcuate outlet slot in its upper portion to permit gas to escape therefrom to the manifold, a gas inlet line connected to the gas inlet, a pressure regulator connected in said line, a sleeve slidable on the member and having its upper end movable relative tothe opening in the housing for controlling the admission of air from housing with the pressure regulator to maintain a proportional inflow of air to the chamber and gas to the gas inlet and tubular member.

8. A gas mixer adapted to be connected to an internal combustion engine including, a housing having gas and air inlets and also having a common outlet for the gas and airflowing through the housing, fixedmeans within the housing leading from the gas inlet and having a port through which the gas from the inlet may flow into the housing and to the outlet, movable means surrounding the fixed means and adapted to co -act with the port to admit gas into said housing, and a pressure responsive element within the housing and connected withsaid movable means,said element being exposed to the suction of the engine, whereby the movable means is actuated by said suction.

9. A gas mixer adapted to be connected to an internal combustion engine including, a housing having gas and air inlets and also having a common outlet for the gas and air flowing through the housing, fixed means within the housing leading from the gas inlet and having a port through which the gas from the inlet may flow into the housing and to the outlet, movable means surrounding the fixed means and adapted to co-act with the port to admit gas into said housing, said last named means also coacting with the outlet of the housing to control the air admitted to said outlet, and a pressure responsive element within the housing and connected with said movable means, said'element being exposed to the suction of the engine, whereby the movable means is actuated by said suction. v 10. A gas mixer adapted to be connected to an internal combustion engine including, a housing having gas and air inlets and also having a common outlet for the gas and air flowing through the housing, fixed means within the housing leading from the gas inlet and having a port through which the gas from the inlet may flow into the housing and to the oulet, movable means surrounding the fixedmeans and adapted to coact with the port to admit gas into said housing, said last named meansalso co-acting with the outlet of the housing to control the air admitted to said outlet, and a positive cut-off for the gas actuated by said movable means.

11. A gas mixer for an internal combustion en gine having a manifold, a housing having an outlet which is adapted to be connected to the intake manifold of the engine, said housing also having a gas inlet and an air inlet, a gas passage leading from the gas inlet and having its outlet end this posed within the housing, movable means surrounding the gas passage and adapted to co act with the outlet end of said passage for controlling the admission of gas to the housing and to the outlet of said housing, said means also co-acting with the outlet of the housing for controlling the air flowing from the housing to the outlet whereby the gas and air flowing through the housing ou let and to the manifold is proportioned by the movable means, and a pressure responsive element within the housing and connected with said movable means, said element being exposedto the suction of the'engine, whereby the movable means is actuated by said suction.

12. A gas mixer for an internal combustion engine having a manifold, a housing having an outlet which is adapted to be connected to the intake manifold of the engine, said housing also having a gas inlet and an air inlet, a gas passage leading from the gas inlet and having its outlet end disposed within thehousing, movable meanssurrounding the gas passage and adapted to co-act with the outlet 'end of said passage for controlling the'admission of gas to the housing and, to the outlet of said housing, said means also co-acting with the outlet of the housing for controlling the air flowing from the housing to the outlet whereby the gas and air flowing through the housing outlet and to the manifold is proportioned by the movable means, and a valve for controlling the flow from the gas inlet to the gas passage directly connected and actuated by the movable means.

13. A gas mixer for an internal combustion engine having amanifold', a housing having an outlet which is adapted to be connected to the intake manifold of the engine, said housing also having a gas inlet and an air inlet, a gas passage leading from the gas inlet and having its outlet end disposed within the housing, movable means surrounding the gas passage and adapted to co-act air flowing from the housing to the outlet whereby the gas and air flowing through the housing 

